It is known to use microorganisms to conduct modification of biomass, essentially plant biomass, to produce bioenergy products, for example ethanol.
Current industrial processes only allow the culture and growth of microorganisms for the fermentation and extraction of ethanol at temperatures in the region of 30° C., owing to the fragility of the industrial microorganisms (yeasts) used. They also entail major bioenergy costs to concentrate the ethanol after fermentation, since the yeasts currently used for this fermentation cannot withstand concentrations of more than 100 g/l. Additionally, the fermentation of these yeasts practically only uses C6 sugars, of glucose type.
It is also known to treat biological material, bacterial strains inter alia, to impart improved properties thereto.
For example, U.S. Pat. No. 6,716,631 of S. Del Cardayre et al. describes a method based on iterative cycles of recombination and selection/screening to confer desired properties to whole cells and to whole organisms. The added properties are, for example, increased aptitude for genetic recombination, enhanced genome copy number, increased capacity to express and/or secrete proteins and secondary metabolites.
By taking a molecular genetics approach, the authors propose techniques to modify suitably the genomes of cells and organisms to impart novel, improved properties thereto.
The method described in U.S. Pat. No. 6,716,631 uses a population of different cells, the culturing of these cells to form hybrid cells by protoplast fusion, then the screening or selecting of cells which evolved towards acquiring a desired property, and the repeating of these steps until at least one cell is obtained that has the desired modification. This method is presented as being an advantageous alternative to known methods based on a strain improvement programme.
The protoplasts subjected to said fusion may derive from prokaryotic organisms.
One of the envisaged applications in this US patent is the fermentation for the production, e.g. of ethanol, whose yield and cost it is proposed to improve using said recombination method by shuffling the DNA of the microorganisms used. By way of example, mention is made of the homologous recombination of Rhodococcus, known to catalyze two-phase reactions.
International patent application No. WO01/023526 describes the production and use of bacteria resistant to radiation and able to operate bioremediation, in particular of the genus Deinococcus (notably D. radiodurans and D. geothermalis), modified so as be more efficient for the metabolizing, degradation or detoxifying of inorganic and organic contaminants, such as radionuclides, heavy metals and organic solvents. It is recommended that these bacteria should be manipulated to express heterologous enzymes able to detoxify said elements. The bacterial strains are manipulated to combine a variety of functions encoded by different genes in a single host.
US patent application of I. Narumi et al., published on Sep. 18, 2003 under No. 2003/0175977, describes an endogenous plasmid derived from a strain of D. radiopugnans, pUE30, which can be used as vector able to replicate autonomously in bacteria of genus Deinococcus, and which can be used to construct a shuttle vector also containing a plasmid able to replicate autonomously in E. coli and its derivatives, and able to replicate in a bacterium both of genus Deinococcus and of E. coli. 
U.S. Pat. No. 7,160,715 of C. B. Fliermans describes means to measure the distribution and frequency of in vivo generation of DNA strand breaks. These means comprise the use of a PprA protein derived from Deinococcus radiodurans. 
US patent application published under No. 2004/0224320 on behalf of K. Satoh et al describes a Gram-positive bacterium (Access No ATCC BAA-149 or a mutant thereof) that is isolated and purified. The isolate is able to degrade a large variety of organic contaminants and is suitable for the bioremediation of a variety of organic contaminations, in the presence of ionizing radiation.
Also, a recent monograph on the production of ethanol using fermentation with strains of microorganisms was published under the title “Ethanol Fermentation Strains” by J. R. Hettenhaus, under the aegis of the United States Department of Energy and the National Renewable Energy Laboratory (Dec. 16, 1998). In this document, which summarizes the contributions made by participants in the study concerned, it is pointed out that:                the only micro-organism strains which can be used in existing equipment should be similar to those already used, namely Saccharomyces, Zymomonas and E. coli;         in the short term, the increased fermentation of xylose and arabinose could be the targeted objective, it being specified however that it is of little interest to increase the converting efficacy of the other sugars of hexose or oligomer type;        over the longer term, gains could be achieved regarding higher operating temperatures and combining of the steps of enzyme production, saccharification and hydrolysis.        
There was therefore a need for a method to ferment biomass and to obtain ethanol and optionally other metabolites, which could be implemented under significantly better operating conditions than those of current methods, and which at the same time could be more easily piloted than known methods and capable of leading to fermentation products that are cheaper and easier to upgrade.
The invention is able to bring solutions to these expectations and to provide improved methods to draw benefit from biomass by producing alternative bioenergy products, which are becoming increasingly necessary due to the significant reduction in energy sources of fossil origin.